[Tagamet]

My van was notoriously hard to start all last winter. Got through it but now I'm having a similar problem. Went to leave work on a 50* day and it just wouldn't start. Engine was turning over and cranking, but just wouldn't start. I gave it some gas and kept trying. After about 10 minutes, it started up. Tonight, it just wouldn't start. I tried for about an hour. No gas smell (I had been giving it gas a good bit), I was parked on a slight incline. I got it to level and tried again, nothing. It has been running fine, now all of a sudden, nothing. I haven't checked any injectors or anything. Any help would be appreciated.

Tagamet

 

[TomQuick]

You need to start with the basics. First off, I would check plugs and wires, and air and fuel filters if they haven't been done recently. You should also check to see that you are getting proper fuel pressure.

 

[Tagamet]

I will change the spark plugs and wires when I can get it home, and I'll change the filters as well. It had been running fine but then all of a sudden, it just won't start. One thing that I noticed was that it has problems running when it rains. It acts like it's missing or misfiring, especially when I give it gas. But then after it gets going, it's fine.

Thanks for the help,

Tagamet

 

[TomQuick]

If it won't run good in the rain, it is possible that it is an issue with the ignition system. I once got a car for free because it wouldn't start when it was raining out. I looked at the car for a few minutes, and noticed a small cut in the insulation on the ignition wire between the coil, and the distributor cap. I then looked at the underside of the hood, and noticed a burned spot along the edge of one of the braces. When I lowered the hood, that burned spot was right above the cut in the wire. I put a new set of spark plug wires (and 4 new plugs just for good measure) on the car, and drove it for two years.

Often if the ignition is doing it's job enough to create a spark, the engine will run well enough that you won't realize anything is wrong with it. The engine does loose performance over time as the ignition wears, but it is so gradual that you don't realize there is a difference. Eventually though, things get bad enough that it just can't create the spark anymore, and that is when you realize there is a problem.

At any rate, you can use the service port on the fuel rail to make certain that you are getting fuel pressure, and if that is good, I would look to the ignition first.

 

[Tagamet]

I've never checked fuel pressure on a vehicle before, so that may be above my expertise. It's supposed to be a little warmer on Sunday so that'll be my go get it day.

 

[TomQuick]

There is a schrader valve (like a tire valve) in the fuel rail. You can check there for fuel pressure. The simplest test is just to see if there is indeed fuel under pressure by using a screwdriver to push down the valve a bit while having someone turn the key on. Make sure to cover the valve / screwdriver with a rag so fuel doesn't spray all over the place, and don't blame me if you manage to spray fuel in your eyes, or set your van on fire, in other words be careful. If you don't get any fuel, or the pressure seems very low then you need to look at the fuel system. If gas squirts out under decent pressure, then look for a different problem like the ignition system, or a bad sensor.

 

[TomQuick]

Oops, I double posted.

 

[Tagamet]

Is there any way to check the wire that gets voltage to my fuel pump to make sure that isn't the problem? I'm still working...

Thanks again,

Tagamet

 

[TomQuick]

There is a way, I don't think it is terribly easy. While I don't have any experience with the Caravans in this area, I believe that I've read elsewhere that the only way to access the fuel pump on these vehicles is to drop the tank. You might be able to find the wiring harness which leads to the fuel pump, and test it before it vanishes up above the gas tank. You should be able to tell by listening at the fuel filler carefully while someone turns the key on if the pump is working or not. When the key is turned on, you should be able to hear a hum from the fuel filler for a second or two.

 

[acton mike]

when you first switch on the ignition, you should hear a whine from the fuel pump

sometimes it is hard to hear over the chimes and bells for door open, seat belt not latched, etc

so, you can get an assistant to switch the ignition to the on position while you lay on the ground at the back and you should hear the pump come on

The trick with the schrader valve on the fuel rail is a good way to see if you are getting fuel to the rail; it will tell you if you have pressure but it won't tell you if you have adequate pressure or adequate volume

inadequate volume will not normally cause a starting problem (unless it is exceedingly low) but it will hamper performance at above idle throttle positions

The key to getting the the bottom of this problem is systematic and thorough testing of the electrical/ignition and fuel systems.

Start by checking to see if you are getting spark at each plug; a healthy spark mind you

if you are getting a spark, then ensure that you are getting fuel to the rail(s)

if you have spark and fuel at the injector rails, then the next step is to determine if these are getting to the cylinders at the right time

since you say that it is hard to start but will eventually light off, then I suggest that the spark and fuel are getting to the cylinders at the right time but the mixture of spark and fuel is not sufficient to support proper combustion

if the spark is healthy and there is fuel at the injectors, then i suggest the coolant temperature is bad - or the information from the sensor is not getting to the ecm; this device tells the ecm /fuel injection how much fuel is needed to fire the engine

if the ecm, because of a bad coolant temp sensor (or the wires leading to/from the sensor/ecm) thinks the engine is at operating temperature, it will not richen up the mix.

Old timers will remember what starting problems a badly adjuster or malfunctioning automatic choke will cause.

So - if you have fuel and spark, check the ECT sensor and wiring

end of sermon

 

[Tagamet]

Thanks for the info. I have a spark (for the front 3 plugs I checked), but no pressure in the fuel rail. I tried to listen through the gas tank, but didn't hear anything. I'll go under the van and see if I can hear the fuel pump working. Is there a separate fuse for the fuel pump I can check? I've switched relays, but that didn't help either. Where can I check for voltage to the pump that isn't too involved?

Tagamet

 

[TomQuick]

If there is no pressure at the rail, then you have narrowed your problem down considerably.

 

[Tagamet]

I'm going to listen under my van like action mike suggested. When I changed the front spark plugs & wires, I shot a little ether in one of the cylinders and it acted like it wanted to start up. I've got a new fuel filter that should be relatively easy to replace, I just hope it's not a fuel pump issue. I definitely need to check that voltage. I might disconnect my fuel filter and try to start it up and have something to catch the gas in.

Tagamet